Ventilation fan



FIG. 1 is a perspective view according to our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left-side elevational view thereof;

FIG. 5 is a right-side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 1; and,

FIG. 9 is an exploded perspective view of our new design shown in FIG. 1.

The broken lines shown in figures illustrate environmental structures and form no part of the claimed design. 

CLAIM The ornamental design for ventilation fan, as shown and described. 